Edwin



EDWIN O. BARSTOW, 0F MIDLAND, MICHIGAN, ASSIGNOR TO THE DOW CHEMICALCOMPANY, OF MIDLAND, MICHIGAN, A CORPORATION O F MICHIGAN.

METHOD OF MAKING MAGNESIUM CHLORID AND THE LIKE.

No Drawing.

T c all whom it may concern.

Be it known that I, EDWIN O. BARs'row, a

citizen of the United States, and a resident of Midland, county ofMidland, State of Michigan, have invented a new and useful Improvementin Methods of Making Magnesium Chlorid and the like, of which thefolcated to the making of magnesium chlorid.

and the like, consists, in efiect, of a modification of the generalprocess for making this product described in my co-pendmg applicationfiled June 6, 1916, Serial No. 101,928.

The object of the invention is to provide a method or process for theproduction of magnesium chlorid, either 1n solid form or in solution,from any brine containing calcium" chlorid, as for example from thenatural brines which occur in the Michigan district, and contain, inaddition to calcium chlorid, magnesium chlorid and sodium chlorid asWell as a trace of iron chlorid. The object of the invention is notmerely to secure magnesium chlorid as an ultimate product, butincidentally to produce by-products of value, thereby obviouslydecreasing the cost of- I manufacture of both such products.

To the accomplishment of the foregoing and related ends, said invention,then, con- 7 sists of the steps hereinafter fully described andparticularly pointed out in the claims, the following descriptionsetting forth in detailcertain steps embodying the invention, but suchdescribed steps constituting only one of various Ways inwhich theprinciple of the invention may be used.

In carrying out my improved method, whether working with a brinecontaining calcium chlorid alone or in conjunction with sodium andmagnesium chloride, I first treat such brine with a suitable acidsulfate, as for example vniter cake, which is sodi um acid sulfate(NaHSO The reaction,

Where such niter cake is addedelirectly -to the chlorid, may berepresented as follows:

mn'sogcmuwiso:

CaSO 2H O+NaCl+HCL The-calcium sulfate resulting from the foregoingreaction is separated from the mixture by filtration, and, after beingWashed Specification of Letters Patent.

Patented June 3, 1919.

Application filed June 6. 1916. Serial No 101,924.

with water, gives a product commercially used as a paper filler.

The filtrate remaining, then, contains the sodium chlorid andhydrochloric acid resuiting from the foregoing reaction, and in additionsuch sodium chlorid and magnesiumrchlorid, if any, as were present inthe original brine. There will also be a little calcium sulfate in thesolution, due to the solubility of the latter in the presence of theacid brine.

The next step in the process consists in adding-to such solution amagnesium compound capable of neutralizing hydrochloric acid to formmagnesium chlorid,-such com-' pound being added in quantity s'ufiicientto neutralize the free hydrochloric acid present in such solution.Magnesium oxid, car bonate or hydrate, for example, may be thus used thelatter being preferred in practice,

in w ich event the reaction is as follows:

As indicated, the hydrochloric acid reactsf .wlth the magnesium hydrateto form magnesium chlorid, and at the same time the neutralization ofsuch acid decreases the solubility of the calcium sulfate which was insolution, causing a considerable portion of it to be precipitated ascalcium sulfate (CaSOQQl-LO), although there still remains a smallquantity in the solution. For some uses the presence of this smallquantity of the calcium sulfate is not objectionable, and in such casethe residual solution may be at once evaporated until the sodium chloridseparates out, this taking place at a gravity of about 34 Be. Themagnesium chlorid mother liquor thus left may then, in turn,-beevaporated down, until it corresponds in composition to magnesiumchlorid with water of crystallization represented by the formula ('MgC1fiI-I O) when it may be drawn off into drums and allowed to cool andsolidify.

In case, however, it is preferred to remove the last of the calcium insolution,

this may be accomplished by adding magnesiimnsulfite to such solution,the resulting reaction being represented as follows magnesium chloridwhich forms the final product, but the quantity will be very small Thissolution of mixed sulfates may then be added to a calcium chlorid brine,whereupon magnesium chlorid is formed in accordance with the followingreaction Other modes of applying the principle of my invention may beemployed instead of the one explained, change being made as regards the.process herein disclosed, provided the step or steps stated by any oneof the following claims or the equivalent of such stated step or stepsbe employed.

I therefore particularly point out and distinctly claim as my invention1- 1. The method of making magnesium chlorid from a solution containingcalcium chlorid which consists in reacting between such chlorid,magnesium hydrate, and an alkali metal acid sulfate, in such order as toprecipitate calcium sulfate and leave magnesium chlorid in solution,substantially as described.

2. The method of making magnesium chlorid from a. solution containingcalcium chlorid which consists in reacting between such chlorid,magnesium hydrate and sodium acid sulfate, in such order as toprecipitate calcium sulfate and leave magnesium chlorid in solution,substantially described.

3. In a method of making magnesium chlorid from a brine containingcalcium chlorid, the steps which consist in adding an alkali metal acidsulfate to such brine, whereby calcium sulfate is precipitated withformation of hydrochloric acid in solution; separating out such calciumsulfate and addingto the solution amagnesium compound .adapted toneutralize such acid with formation of magnesium chlorid.

4. In a method of making magnesium chlorid from a brine containingcalcium chlorid, the steps which consist in adding sodium acid sulfateto such brine, whereby calcium sulfate is precipitated with formation ofhydrochloric acid in solution; separating out such calcium sulfate andadding to the solution a magnesium compound adapted to neutralize suchacid with forma tion of magnesium chlorid.

In' a method of making magnesium chlorid from a brine containing calciumchlorid, the steps which consist in adding sodium acid sulfate to suchbrine whereby calcium sulfate is precipitated with formation ofhydrochloric acid in solution separating out such calcium sulfate andadding to the solution a quantity of magnesium hydrate sufficient toneutralize such hydrochloric acid with formation ofmagnesium chlorid.

